Cytokines are soluble extracellular proteins or glycoproteins that are crucial intercellular regulators and mobilizers of cells engaged in innate as well as adaptive inflammatory host defenses, cell growth, differentiation, cell death, angiogenesis, and development and repair processes aimed at the restoration of homeostasis. Cytokines are released by various cells in the body, usually in response to an activating stimulus, and they induce responses through binding to specific receptors on the cell surface of target cells. Cytokines can be grouped by structure into different families and their receptors can likewise be grouped.

Conserved domains that are specific hits to the proteins involved in biosystems, representing high confidence functional annotations. The association between the proteins and biosystems was made using the method described in the data processing section of the BioSystems help document.

HomoloGene records that are linked to the proteins involved in the biosystem. The HomoloGene records list putative orthologs of the genes that coded the proteins. The association between proteins and biosystems was made using the method descibed in the data processing section of the BioSystems help document.

Records from the Online Mendelian Inheritance in Man (OMIM) database that are linked to the Entrez Gene records associated with a BioSystem. The association between genes and biosystems was made using the method descibed in the data processing section of the BioSystems help document.

BioAssays whose protein targets are involved in biosystems. The association between the proteins and biosystems was made using the method described in the data processing section of the BioSystems help document.

3D macromolecular structures of proteins involved in biosystems. The association between the proteins and biosystems was made using the method described in the data processing section of the BioSystems help document.